Parasitic causes of prolonged diarrhoea in travellers - diagnosis and management

BACKGROUND

Prolonged infectious diarrhoea in the returning traveller is generally caused by protozoal and occasionally by helminth parasites.

OBJECTIVE

This article provides a framework for the diagnosis, management and prevention of the diseases that cause persistent diarrhoea in the traveller.

DISCUSSION

A large proportion of disease is caused by Giardia lamblia, Cryptosporidium parvum and Entamoeba histolytica. However, given the ease of travel with comorbid conditions such as human immunodeficiency virus, there is an expanding list of organisms that can cause persistent diarrhoea. An awareness of the likely aetiological agents and their clinical features enables a more effective diagnosis and management of the patient's condition using an appropriate antiparasitic agent. Prevention strategies need to be initiated before travel and should consist of simple but memorable advice. Noninfectious causes of diarrhoea should be considered as diarrhoea can be a prominent feature of conditions such as hyperthyroidism or coeliac disease.

Giardiasis surveillance--United States, 2009-2010

PROBLEM/CONDITION

Giardiasis is a nationally notifiable gastrointestinal illness caused by the protozoan parasite Giardia intestinalis.

REPORTING PERIOD

2009-2010.

SYSTEM DESCRIPTION

State, commonwealth, territorial, and two metropolitan health departments voluntarily report cases of giardiasis through CDC's National Notifiable Diseases Surveillance System.

RESULTS

During 2009-2010, the total number of reported cases of giardiasis increased slightly from 19,403 for 2009 to 19,888 for 2010. During this period, 50 jurisdictions reported giardiasis cases. A larger number of case reports were received for children aged 1-9 years than with other age groups. The number of cases peaked annually during early summer through early fall.

INTERPRETATION

Transmission of giardiasis occurs throughout the United States, with more frequent diagnosis or reporting occurring in northern states. However, state incidence figures should be compared with caution because surveillance capacity differs between states. Giardiasis is reported more frequently in young children, which might reflect increased contact with contaminated water or ill persons.

PUBLIC HEALTH ACTION

Local and state health departments can use giardiasis surveillance data to better understand the epidemiologic characteristics and the disease burden of giardiasis in the United States, design efforts to prevent the spread of disease, and establish research priorities.

Intestinal parasitic infection and nutritional status among school children in Angolela, Ethiopia

INTRODUCTION

Gastrointestinal parasitic infections are most prevalent in populations with low household income, poor handling of personal and environmental sanitation, overcrowding, and limited access to clean water. We conducted this study to estimate the prevalence of parasitic infection and nutritional status, and to evaluate the extent to which the two are associated among schoolchildren in rural Ethiopia.

METHODS

This is a cross sectional study of 664 students aged from 6 to 19 years old from Angolela, Ethiopia. Socio-demographic information was collected using a structured questionnaire. Anthropometric measurements were taken at the time of interview. Examinations of fecal samples for helminthic and protozoan parasitic infections were performed. Logistic regression procedures were employed to evaluate the association between stunting, underweightedness, and wasting with parasitic infections. RESULTS. One-third of the participants were found to have a protozoan infection, while 7.1% were found to have a helminthic infection. Approximately 11% of the students were stunted, 19.6% were wasted, and 20.8% were underweight. Severely underweight boys were 3.88-times as likely as boys of adequate weight (odds ratio OR = 3.88, 95% confidence interval CI: 1.12-13.52) to be diagnosed with protozoan infections. Among girls, those who were severely stunted were approximately 12 times (OR = 11.84, 95%CI: 1.72-81.62) as likely to be infected with a helminthic parasite, than those who were not. Overall, there was a deficit in normal growth patterns as indicated by lower than average anthropometric measures. DISCUSSION AND CONCLUSIONS. There is a high prevalence of intestinal parasitic infections. Stunting, wasting, and underweightedness were also prevalent, and showed patterns of associations with intestinal parasitic infections. Efforts should be made to strengthen and expand school and community-based programs that promote inexpensive, though effective, practices to prevent the spread of parasitic diseases. Initiatives aimed at improving the nutritional status of school children are also needed.

Synergistic effects between rotavirus and coinfecting pathogens on diarrheal disease: evidence from a community-based study in northwestern Ecuador

In developing countries where diarrheal disease is a leading cause of morbidity and mortality in children under 5 years of age, enteric coinfection is common. There is little understanding, however, of the biologic interaction between coinfecting pathogens. The authors investigated the potential for synergistic interaction between coinfecting pathogens on diarrhea pathogenesis using an epidemiologic framework. They conducted community-based, case-control studies in 22 communities in northwestern Ecuador between 2003 and 2008. Risk ratios of diarrhea associated with single infections and coinfections were estimated. Interaction between coinfecting pathogens was assessed through departure from risk ratio additivity and multiplicativity after adjustment for age. On the additive scale, the authors found departure from the null value of 0 for rotavirus-Giardia coinfections (interaction contrast ratio = 8.0, 95% confidence interval: 3.1, 18.9) and for rotavirus-Escherichia coli coinfections (interaction contrast ratio = 9.9, 95% confidence interval: 2.6, 28.4). On the multiplicative scale, they found departure from the value of 1 for rotavirus-Giardia coinfections (multiplicative interaction = 3.6, 95% confidence interval: 1.3, 8.7). This research provides epidemiologic evidence for synergism between rotavirus and other enteric pathogens. During coinfection, the pathogenic potential of each organism appears to be enhanced. The potential for pathogenesis to be more severe in the presence of a rotavirus coinfection amplifies the need for rotavirus vaccination.

Detection of Giardia duodenalis assemblages A and B in human feces by simple, assemblage-specific PCR assays

The flagellated protozoan Giardia duodenalis is a common gastrointestinal parasite of mammals, including humans. Molecular characterizations have shown the existence of eight genetic groups (or assemblages) in the G. duodenalis species complex. Human infections are caused by assemblages A and B, which infect other mammals as well. Whether transmission routes, animal reservoirs and associations with specific symptoms differ for assemblage A and assemblage B is not clear. Furthermore, the occurrence and clinical significance of mixed (A+B) infections is also poorly understood. To date, the majority of PCR assays has been developed to identify all G. duodenalis assemblages based on the use of primers that bind to conserved regions, yet a reliable identification of specific assemblages is better achieved by ad hoc methods. The aim of this work was to design simple PCR assays that, based on the use of assemblage-specific primers, produce diagnostic bands of different lengths for assemblage A and B. We first generated novel sequence information from assemblage B, identified homologous sequences in the assemblage A genome, and designed primers at six independent loci. Experiments performed on DNA extracted from axenic cultures showed that two of the six assays can detect the equivalent of a single cyst and are not negatively influenced by disproportions between DNA of each assemblage, at least up to a 9∶1 ratio. Further experiments on DNAs extracted from feces showed that the two assays can detect both assemblages in single tube reactions with excellent reliability. Finally, the robustness of these assays was demonstrated by testing a large collection of human isolates previously typed by multi-locus genotyping.

Giardia duodenalis is an important cause of diarrhoea in humans worldwide, even if the burden of infection is higher in developing countries where the poor sanitary conditions favour the contamination of water and food with infective cysts. The parasite is considered as a species complex that comprises at least eight distinct genetic groups, referred to as assemblage A to H. Humans are infected only by assemblages A and B, which can only be distinguished by molecular methods. The clinical manifestations of giardiasis in humans are highly variable and range from the absence of symptoms to acute or chronic diarrhoea. Since genetic traits that influence the virulence are yet unknown, the identification of the assemblage is considered a primary element in the study of human giardiasis. Current methods are time consuming and/or require expensive instruments. Here, we describe the development and application of single step PCR methods that allow to detect and distinguish assemblages A and B from human fecal specimens simply by gel electrophoresis of the amplification products. The novelty of the assays described in our manuscript is the reliability in detecting mixed infections and the applicability of the methodology in laboratories with basic molecular equipment.

[Asthenia or anaemia. What is the diagnosis?]

Giardiasis is one of the most frequent parasitic infections in the world that must be considered in every patient with persistent diarrhoea or digestive tract and/or malabsorption symptoms after a foreign trip or in the immigrant population, although its presentation is not always the typical. A 25 year old woman from Equatorial Guinea was seen at the clinic due to several months of asthenia. The Laboratory analyses showed normocytic and normochromic anaemia and high erythrocyte sedimentation rate (ESR). Throughout the presentation of the case report the differential diagnoses of asthenia, normocytic and normochromic anemia and high ESR will be discussed until the final diagnosis of giardiasis was made.

Molecular characterization of Giardia parasite isolated from stool samples collected from different hospitals in Taif City (Saudi Arabia)

Giardia parasite is prevalent endemically in Taif city. Infection is more prevalent in children under 5 years old and elderly people. The sickness is more intense in immunecompromised people. The disease is usually diagnosed by stool examination by the microscope, for the identification of the both trophozoite and cyst stages. Usually the disease is overlooked during stool analyses due to the minute size of the parasite and due to the scarcity of infection sometimes. Hence molecular characterization or diagnosis is used as an alternative method for the diagnosis of infection. Molecular characterization is based on polymerase chain reaction (PCR). This technique is regarded as a highly sensitive and accurate method of diagnosis. The prevalence of Giardia duodenalis was 15% in stool samples collected from different hospital in Taif. By means of RAPD technique, most G. duodenalis isolates were genetically similar, forming two main groups, with about 60% of similarity one another.

[ELISA and spontaneous sedimentation technique for the diagnosis of Giardia lamblia infection in stool samples of Peruvian children]

OBJECTIVE

To compare a commercial coproantigen ELISA kit and the technique of spontaneous sedimentation in tube (TSET) for the diagnosis of Giardia lamblia in fecal specimens from children in a Peruvian endemic area.

MATERIAL AND METHODS

174 fecal samples were analyzed by TSET and 2nd Generation Giardia ELISA kit.

RESULTS

51 samples were positive by ELISA and 49 by TSET.

CONCLUSIONS

The ELISA was highly sensitive and specific, simple and fast. However, the very good agreement, high precision, low cost and ability to detect other intestinal parasites makes use of TSET recommended for laboratory diagnosis in endemic areas of Peru.

Impact of Giardia lamblia on growth, serum levels of zinc, copper, and iron in Egyptian children

The aim of this study is to evaluate the serological levels of zinc, copper and iron in Giardia lamblia-infected children and to study the effect of giardiasis on their weight compared to controls. We studied 30 children, 1-10 years old, who attended the outpatient clinics of Cairo University Pediatric Hospital, with gastrointestinal complaints and diagnosed as having giardiasis by stools examination, they were enrolled as a study group. The control group consisted of 30 age- and sex-matched healthy children, free of gastrointestinal complaints and free of giardiasis. Serological levels of zinc, copper, and iron were measured by atomic absorption spectrophotometer. The infected group had significantly lower weight, serum iron, and zinc than controls (P = 0.035, <0.001, and <0.001 respectively) and 63.3% of patients infected with giardiasis were 1-5 years old. In the infected cases, 60% suffered from of abdominal pain, 50% from weight loss, and 40% had intermittent diarrhea. Infected cases with weight percentiles below the fifth had significantly lower serum iron than those with normal percentiles (>5th). In conclusion, most giardiasis-infected children were between 1 and 5 years, with significant affection of weight, abdominal pain, and/or intermittent diarrhea. Serum zinc and iron levels were significantly decreased in the infected group compared to control (P < 0.001).

Hospitalization of Cuban children for giardiasis: a retrospective study in a paediatric hospital in Havana

The medical records of the 185 children who, in 2007, were admitted to the Academic Paediatric Hospital 'Centro Habana', in the Cuban capital of Havana, because of giardiasis were analysed retrospectively. A standardized form was used to collect data on the socio-demographic characteristics, clinical features, laboratory diagnosis, treatment and length of stay of each child. Information on the 15 children who had incomplete medical records was excluded from the data analysis. Of the remaining 170 children, 85 (50·0%) were aged 1-4 years, 97 (57·1%) were male, and 106 (62·4%), 92 (54·1%) and 69 (40·6%) had presented with diarrhoea, vomiting, and/or abdominal pain, respectively. Most (91·2%) of the cases had been diagnosed by the microscopical examination of a duodenal aspirate, and the drugs that had been most used frequently were quinacrine and tinidazole, which had been given to 72 (42·4%) and 62 (36·5%) of the cases, respectively. The mean length of hospital stay was 4·9 days. Such information on the clinical characteristics of giardiasis among children living in an endemic area may be valuable to paediatricians and public-health officials who wish to screen for the disease.

Parasitological stool examination from children without the typical symptoms of parasitic disease

Most parasitic intestinal infestations in humans are sub-clinical and, therefore, they are rarely diagnosed. A number of general, non-specific symptoms of parasitic invasions are often attributed to other diseases. A parasitological examination of feces performed as part of this study confirmed the presence of intestinal parasites in 21.6% of samples. Among the patients who reported 6 different symptoms, the percentage of parasite-positive samples reached 80%. The obtained results suggest that coproscopic tests may establish the diagnosis in unclear cases, particularly in children. Many parasitic invasions are zoonoses and pets owe a reservoir. In view of the above, the results for pet owners and non-pet owners were compared in the study. There was no direct correlation between pet ownership and the incidence of parasitic infections.

[Immunocompromised HIV patient with lymphadenopathy and fever]

The case of a immunocompromised HIV patient with fever and lymphadenopathy discussed in an anatomo-pathological round. This complex clinical case was used as an opportunity to discuss the broad differential diagnosis of fever in an immunocompromized individual with multiples lymphadenopathies. Clinical reasoning leading to the probable diagnosis based on clinical, biological and radiological informations is not only a difficult task for the speaker but also a rich source of learning opportunities for our medical community.

Evaluation of an inhouse rapid ELISA test for detection of giardia in domestic sheep (Ovis aries)

Sheep (Ovis aries) are increasingly used at our institution as models of human disease. Within the research environment, routine husbandry and handling of sheep has potential for transmission of zoonotic agents, including Giardia. The prevalence of Giardia in sheep may approach 68%. Classic diagnostic testing involves microscopic examination for fecal cysts or trophozoites; however, limitations of microscopy include time, labor, and potential false-negative results due to intermittent shedding. We wished to determine whether a commercial rapid ELISA used for Giardia detection in dogs and cats could be used in sheep. Fecal samples collected from sheep (n = 93) were tested with a combination of 6 methods: reference laboratory fecal flotation, reference laboratory ELISA, inhouse fecal flotation, and commercially available tests (enzyme immunoassay, direct fluorescence antibody assay, and rapid ELISA). Prevalence of Giardia infection in facility sheep was 11.8% (11 of 93 animals). Of the 11 samples considered positive, 3 were confirmed by multiple testing methods, and 5 were positive by microscopy alone. Inhouse fecal flotation for 8 samples was positive on only 1 of 2 consecutive testing days. The rapid ELISA test exhibited 0% sensitivity for sheep giardiasis. Overall, the examined methods had low sensitivities and low positive predictive values. Despite limitations, microscopic analysis of repeat fecal samples remained the most accurate diagnostic method for ovine giardiasis among the methods tested.

Giardia infection in cats

The protozoon Giardia duodenalis is a common gastrointestinal parasite of cats. While most Giardia-infected cats are asymptomatic, acute small bowel diarrhea, occasionally with concomitant weight loss, may occur. Giardia poses a diagnostic challenge, but newer tests, including a commercially available ELISA kit, have improved clinicians' ability to obtain an accurate diagnosis. Several treatment options have been reported, and although none has been shown to be universally effective, most cases can be successfully managed with drug therapy, supportive measures, and environmental control. Current recommendations suggest that combination therapy with fenbendazole and metronidazole may be the safest, most effective treatment option for symptomatic cats.

A case of giardiasis expressing severe systemic symptoms and marked hypereosinophilia

An 88-year-old Japanese woman was referred to our hospital due to a one-month history of face edema, aphagia, shortness of breath, and skin rush over almost her entire skin. She had no abdominal symptoms. Her peripheral blood count showed a white blood cell (WBC) count of 27.1x10(9)/L with 82.1% eosinophils. Serum non-specific Immunoglobulin E was within a normal range. Soluble interleukin-2 receptor was elevated to 4200U/mL. At first, her eosinophil count was so high that we suspected she had an eosinophilic leukemia or hypereosinophilic syndrome. After admission, cysts of Giardia duodenalis (G. duodenalis) were detected in the patient's feces by microscopic analysis, then she was diagnosed with giardiasis, and 750mg per day of metronidazole was administered for seven days. Her WBC count decreased to 6.0x10(9)/L with 10% eosinophils, and her systemic symptoms improved. At that time her serum IL-5 was within a normal range. A few months later, the patient again complained of skin rush, and G. duodenalis was once again found in her feces. Her serum IL-5 was elevated to 751pg/mL. Metronidazole was administered for two weeks, and her eosinophil count decreased. G. duodenalis is a protozoan parasite, and it is one of the most common waterborne transmission gastrointestinal parasites in the world. G. duodenalis rarely causes hypereosinophilia. To our knowledge, this is the first case report of giardiasis with extreme hypereosinophilia and severe systemic symptoms.

Giardiasis surveillance - United States, 2006-2008

PROBLEM/CONDITION

Giardiasis is a nationally notifiable gastrointestinal illness caused by the protozoan parasite Giardia intestinalis.

REPORTING PERIOD

2006-2008.

SYSTEM DESCRIPTION

State, commonwealth, territorial, and two metropolitan health departments voluntarily report cases of giardiasis through CDC's National Notifiable Disease Surveillance System.

RESULTS

During 2006--2008, the total number of reported cases of giardiasis increased slightly from 19,239 for 2006 to 19,794 for 2007 and decreased slightly to 19,140 for 2008. During this period, 49 jurisdictions reported giardiasis cases; giardiasis is a reportable condition in 45 states (not reportable in Indiana, Kentucky, Mississippi, North Carolina, and Texas). A greater number of case reports were received for children aged 1-9 years and for adults aged 35-44 years compared with other age groups. Incidence of giardiasis was highest in northern states. Peak onset of illness occurred annually during early summer through early fall.

INTERPRETATION

Transmission of giardiasis occurs throughout the United States, with more frequent diagnosis or reporting occurring in northern states. However, state incidence figures should be compared with caution because individual state surveillance systems have varying capabilities to detect cases. The seasonal peak in age-specific case reports coincides with the summer recreational water season and likely reflects increased outdoor activities and exposures such as camping and use of communal swimming venues (e.g., lakes, rivers, swimming pools, and water parks) by young children.

PUBLIC HEALTH ACTION

Local and state health departments can use giardiasis surveillance data to better understand the epidemiologic characteristics and the disease burden of giardiasis in the United States, design efforts to prevent the spread of disease, and establish research priorities.

Prevalence and diagnosis of Giardia infection in dogs and cats using a fecal antigen test and fecal smear

The SNAP fecal enzyme-linked immunosorbent assay (ELISA) Giardia test was used to determine the prevalence of Giardia in dogs and cats with gastrointestinal signs. The test was positive in 241 (13.0%) dogs and 16 (4.1%) cats. Giardia cysts were detected in only 61 of the 241 dogs and 4 of the 16 cats that were test positive.

Unusual presentations of Giardia lamblia; a report of four cases

OBJECTIVE

To create awareness that giardiasis can mimic acute clinical symptomatologies and result in missed diagnosis.

METHOD

The case files of four acute and life threatening presentations that were misdiagnosed initially but later found to be Giardia lamblia infestations from laboratory stool results and responded to treatment for giardiasis were reviewed.

RESULTS

One of the cases was diagnosed as food poisoning, a second as a case of hypovolemic shock and the third also as a hypovolemic shock, though also considered to have sepsis and the last, a case of acute exacerbation of asthmatic attack. Three of the cases were less than 24 months and vomiting was seen in 3 of them.

CONCLUSION

Giardiasis in childhood can be acute and life threatening and should be considered in such ill children, especially if they also have digestive system symptomatology.

Chronic urticaria in a middle-aged woman

We report the case of a 56-year-old female who suffers from chronic urticaria and digestive symptoms, suggesting parasitic infection. Neither repetitive ova and parasite examinations in stools, nor duodenal aspiration examination reveals any parasite. The patient is treated by tinidazole, but the symptoms reappear ten days later. An additive ELISA test on stool remains positive for Giardia Lamblia; the patient receives once more tinidazole and symptoms totally disappear. This case report illustrates that the association between urticaria and digestive symptoms should guide the clinician to the diagnosis of Giardia Lamblia infection, and it shows the importance of a rapid and highly sensitive diagnostic test for giardiasis, like the ELISA test.